III-V group nitride semiconductors are diversely applied to an optical device such as a blue/green light emitting diode (LED), a high speed switching device such as a Metal Semiconductor Field Effect Transistor (MOSFET) and a Metero junction Field Effect Transistor (HEMT), and a light source of a lightening or displaying device.
The nitride semiconductor is mainly used as an LED or a laser diode (LD), and also researches for improving a manufacturing process or light efficiency has been continuously conducted.